One of the challenges in drug delivery is the ability to target the treatment to a particular area of the body or a particular biological tissue and maintain delivery at the area or tissue. In most instances, repetitive treatments are needed over the course of days to weeks in order to maintain the necessary therapeutic level of an active agent. Simply stated, this approach is inconvenient and costly.
For example, sudden sensorineural hearing loss (SSNHL) is a disease that attacks 4,000 Americans annually and is characterized by near complete hearing loss in as little as a few hours. The most efficacious treatment for SSNHL consists of frequent injections of an anti-inflammatory steroid into the middle ear, which diffuses into the inner ear via the round-window membrane (RWM). The invasive nature of these injections, especially if delivery is desired directly on the surface of the RWM, results in low patient compliance and a loss of efficacy. Thus, SSNHL patients and patients having other conditions that require a localized long-term treatment protocol would benefit from a drug delivery platform that permits the use of a single injection while providing an extended-release profile of the therapeutic agent.